Such printing presses are known as such in the art, in particular from International PCT Publications Nos. WO 2005/000585 A1, WO 2008/102303 A2, WO 2009/156926 A2 and European Patent Publication No. EP 2 433 798 A1, which publications are all incorporated herein by reference in their entirety.
European Patent Publication No. EP 2 433 798 A1 in particular discloses a sheet-fed printing press 100 as schematically illustrated in FIG. 1, which printing press 100 comprises a silk-screen printing group 2 adapted to apply at least one ink or varnish vehicle containing magnetic or magnetisable flakes on a sheet-like substrate. Individual substrates are fed in succession from a sheet feeder station 1 to the silk-screen printing group 2, which silk-screen printing group 2 includes first and second screen printing units 2b, 2c cooperating with a common impression cylinder 2a. In the illustrated example, an upper side of each substrate (indicated by the white triangles in FIG. 1) is thus provided with one or more patterns of an ink or varnish vehicle containing the magnetic or magnetisable flakes and the thus-printed substrates are then transported in succession from the printing group 2 to a downstream-located magnetic orientation unit 10 which is positioned along the path of the substrate and is designed to induce an optically-variable effect in the ink or varnish vehicle prior to drying/curing thereof. This optically-variable effect is induced by means of the magnetic orientation unit 10 which includes at least one magnetic-field-inducing device adapted to orient the magnetic or magnetisable flakes contained in the ink or varnish vehicle applied on the substrate. Advantageously, the magnetic orientation unit 10 is of a type comprising a rotating cylinder assembly 11 (see also International PCT Publication No. WO 2008/102303 A2 already cited hereinabove).
As shown in FIG. 1, the substrates are preferably transported from the printing group 2 to the magnetic orientation unit 10 by means of a first conveyor system 21 (the rotating cylinder assembly 11 also acting as transport cylinder in such example) and then from the magnetic orientation unit 10 to a second conveyor system 22 which transports the substrates onwards, e.g. to a sheet delivery station 4.
As taught by European Patent Publication No. EP 2 433 798 A1, a drying/curing unit 15 is provided proximate to where the rotating cylinder assembly 11 is located. A further drying/curing unit 5 may be provided downstream of the magnetic orientation unit (e.g. along the path of the second conveyor system 22) in order to finalise drying/curing of the ink or varnish vehicle applied on the substrate.
A drawback of the known solutions as for instance taught by European Patent Publication No. EP 2 433 798 A1 resides in the fact that the provision of the additional drying/curing unit compromises accessibility to the magnetic orientation unit.
Furthermore, maintenance operations on both the drying/curing unit and the magnetic orientation unit are made more difficult.
There is therefore a need for an improved solution.